The primary objective of this contract shall be to provide support services for the Environmental Epidemiology Branch (EEB), Epidemiology & Biostatistics Program (EBP), Division of Cancer Etiology (DCE), National Cancer Institute (NCI), by continuing the follow-up of a cohort of DES-exposed individuals for the estimation of long-term cancer risk. In addition, specific sub-studies of non-cancer endpoints, using the resource of the combined cohort, shall be designed and conducted. The recommendations of the i 992 NIH workshop on DES shall be relied upon to form priorities for specific studies. A "Steering Committee" shall be formed to guide and coordinate future research efforts in the DES-exposed and comparison cohorts.